We propose a 5-year continuation of the McLean Study of Adult Development (MSAD), the first large-scale, prospective study of the long-term course of borderline personality disorder (BPD). We will obtain a minimum of 16 years of follow-up on 290 patients who met DIB-R and DSM-III-R criteria for BPD and 72 axis II comparison subjects who met DSM-III-R criteria for another personality disorder (and neither criteria set for BPD). After 10 years of follow-up, we are still following 93% of the surviving borderline patients (and 86% of the surviving axis II comparison subjects). During the years of follow-up, we have found that remissions of BPD are more common than expected and recurrences of BPD are quite rare. We have also found that a complex" model of borderline psychopathology best describes the course of the 24 symptoms of BPD that we are following. In this "complex" model, some symptoms are seen as acute as they resolve relatively rapidly and other symptoms are seen as temperamental as they resolve relatively slowly. Taken together, these findings suggest that BPD has a better prognosis than commonly thought. However, many borderline patients are now obese and suffering from a variety of obesity-related medical conditions. We believe that these findings warrant further investigation into the course of borderline psychopathology, psychosocial functioning, co-occurring axis I and II disorders, temperament, psychiatric treatment and medical conditions and medical treatments (AIM 1: Description). We also believe that these findings warrant further investigation into the predictors of five main outcomes: remission from BPD, recurrence of BPD, attainment of good psychosocial functioning, attempted suicide, and completed suicide (AIM 2: Prediction). Subjects will be assessed at two-year intervals by raters who are blind to all previously collected information. This proposed continuation will result in useful knowledge about the course of borderline psychopathology, with direct implications for patients, their families, and the clinicians treating them.